In a known method of the said type, the blood is extracted from small cuts or punctures by means of small capillary tubes in which the blood automatically rises as a result of the capillary action. For the purpose of examining or treating the blood, the blood had to be blown out into a micro-container by means of the mouth or a separate blower. This method is either dangerous for the operator or can be carried out only at a relatively great expense, it also being disadvantageous that a portion of the small quantity of blood is lost.
A reservoir has already been proposed for emptying these known small capillary tubes and is characterised by a tubular body which is closed at its bottom end and whose interior space is subdivided by a partition to form a side pocket for receiving one or a plurality of small capillary tubes, and a main chamber which tapers conically downwardly and opens into a collecting pocket of circular cross section, wherein the bottom of the side pocket lies above the top edge of the collecting pocket, and the partition leaves free a communication between the side pocket and the main chamber and does not quite reach to the bottom of the side pocket. The side pocket is loaded with the small capillary tubes filled with blood and, if required, the top of the container is closed by means of a plug. Centrifuging is then carried out, wherein the blood located in the capillary tubes is centrifuged downwardly therefrom and, by way of the bottom of the side pocket and the connection between the latter and the main chamber, enters the main chamber where the blood collects in the collecting pocket. The blood or, after appropriate treatment, the serum or plasma, can be extracted from the collecting pocket by means of a micropipette.